title: Should we inhibit gastric acid secretion before cardiac surgery?
abstract: Stress can decrease intragastric pH and cause erosion of gastric mucosa. Because cardiac surgery and cardiopulmonary bypass represent a major stress, the effects on intragastric pH of an H2-receptor antagonist, ranitidine, and an M1-muscarinic antagonist, pirenzepine, were evaluated. Intragastric pH was measured throughout elective cardiac surgery in 60 patients by a digital pH-meter during fentanyl-diazepam-nitrous oxide (50%) anesthesia. The gastric content was sampled at closure of the chest for bacterial count. Oral preoperative medication given randomly included (n = 20 in each group) 0.3 mg/kg diazepam 1 h before induction (group 1); diazepam plus ranitidine (150 mg) 1 h before induction (group 2); and diazepam plus pirenzepine (50 mg) on the evening before surgery and 1 h before induction of anesthesia (group 3). At induction intragastric pH was higher in group 2 (mean +/- SD = 7.42 +/- 1.07) than in group 1 (5.28 +/- 2.14) (P less than 0.01) but was not significantly different in group 3 (5.78 +/- 1.89) than in group 1. In no group did intragastric pH change significantly during surgery. Gastric juice was sterile in 92% of group 1, in 25% of group 2, and in 71% of group 3 patients (P less than 0.01). Postoperatively no gastrointestinal complications occurred, but there was a trend toward more patients developing nosocomial pneumonias in groups 2 and 3 (15%) than in group 1 (0%) (P = 0.06). Intraoperative intragastric pH is relatively high after diazepam premedication, thus the preoperative addition of ranitidine or pirenzepine would not be necessary and may possibly be hazardous.
authors.affiliation: Département d'Anesthésie Réanimation, Hôpital Cardiovasculaire et Pneumologique L. Pradel, Lyon, France.
authors.forename: J J
authors.initials: JJ
authors.lastname: Lehot
authors.forename: R
authors.initials: R
authors.lastname: Deleat-Besson
authors.forename: O
authors.initials: O
authors.lastname: Bastien
authors.forename: Y
authors.initials: Y
authors.lastname: Brun
authors.forename: P
authors.initials: P
authors.lastname: Adeleine
authors.forename: J
authors.initials: J
authors.lastname: Robin
authors.forename: S
authors.initials: S
authors.lastname: Estanove
mesh_terms: D000328:Adult; D000368:Aged; D006348:Cardiac Surgical Procedures; D005260:Female; D005744:Gastric Acid / Q000378:metabolism*; D005745:Gastric Acidity Determination; D005750:Gastric Juice / Q000382:microbiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010890:Pirenzepine / Q000627:therapeutic use*; D011014:Pneumonia / Q000209:etiology; D011183:Postoperative Complications; D011292:Premedication; D011899:Ranitidine / Q000627:therapeutic use*
chemical_list: D010890:Pirenzepine; D011899:Ranitidine